All of your files...Windows, programs, data files...are installed on the hard drive. They are installed on a "bed" which is the file system (NTFS in your case).
Typically, problems with either the file system or the hard drive itself...may cause the system problems with reading/accessing the files used.
It's hard to generalize and say what type of problems can be caused...the symptoms/manifestations vary.
That's why there are standard diagnostic tests which can be run on a given hard drive...to see if there is a problem which adversely impacts the functioning of the system.
Taken from http://partition.radified.com/:• HARD DRIVES are like houses, because each house (hard drive) has its own rooms (partitons). Houses come in different sizes, and may contain any number of rooms (partitions). They can also be expensive, and some are built better than others.
Adding a second hard drive to your system is like buying a vacation home at the shore or the lake. It could be used to store all your digital Media, such as your MP3 collection, your lossless audio files, or photographs.
• PARTITIONS are like rooms in a house, because they separate different parts of a house into distinct areas for different purposes. For example, the kitchen for cooking, bedroom for sleeping, gaming room for playing Counterstrike. Likewise, you can create a partition for all your Games, and another to store your Back-ups, etc.
• FOLDERS (also called directories) are like areas sectioned off by room-dividers, because they are simple to set-up (create), and easy to remove (delete). They can be changed around without much fuss to suit your needs. But they also have limitations.
Simply put...a hard drive can contain subdivided sections of the hard drive, these areas are called partitions.
To see the partitions and the drives which are part of your system, Start/Run...type diskmgmt.msc and hit Enter or OK.
<<Can I fix it or will it happen again?>>
At the moment, we don't know why you have your problem...as I said, my guess. To confirm/refute that premise, you need to to run a hard drive diagnostic on your system.
At this point, the best thing to do (IMO) would be to see if your data files can be recovered. I would suggest not using your system for this effort...the system of a friend (a system without problems) would be better. After that is done, then you can attempt to determine what is what.
I still need to know the manufacturer of your system...and the model. Once you tell us that, I can suggest the best way to attempt recovery of your files.